This invention relates to an apparatus for automatically cleaning outer surfaces of a building such as a window glass and a wall surface by horizontally moving along such outer surface and, more particularly, to an apparatus of such type particularly suited for cleaning a horizontally continuous outer surface such as a horizontally continuous window glass.
For performing cleaning of a window glass of a multistoried building safely and efficiently, various automatic window cleaning apparatus have been proposed and used. In use, these cleaning apparatus are usually suspended from a roof car or the like device disposed on the roof of the building by means of a wire.
For performing the cleaning work, the prior art automatic window cleaning apparatus is successively lowered vertically from a window of the uppermost floor towards the ground for cleaning a window of each story successively and, after finishing cleaning of a window of the ground floor, the cleaning apparatus is lifted to the uppermost floor and then moved horizontally to a next window of the uppermost floor to reiterate the above cleaning operation from the uppermost floor down to the ground floor.
Such prior art automatic window cleaning apparatus is effective when it is used on windows which are continuously formed in the vertical direction of a building because these vertically continuous windows can be cleaned very effectively by preadjusting the width of the cleaning apparatus to the width of the windows.
It is a recent tendency in the building design, however, to design a building with horizontally continuous windows which are continuously formed horizontally on the same floor but are discontinuous between vertically adjacent floors. The above described prior art window cleaning apparatus which are adapted to move in the vertical direction are incapable of approaching the window glass surface if there is a portion of the building which is projecting between vertically adjacent windows and, accordingly, cleaning of the window glass must be done by a hand work.
For achieving cleaning of such horizontally continuous windows by using the prior art window cleaning apparatus adapted to move vertically, it is conceivable to move the prior art window cleaning apparatus horizontally by horizontally moving the roof car from which the apparatus is suspended. This concept, however, is unworkable because, if such cleaning apparatus suspended from the roof car by wire rope is moved horizontally, such horizontal moving will be accompanied by a great sway of the apparatus with resulting difficulty in realizing smooth horizontal moving of the apparatus and accomplishment of the intended cleaning work. The longer the wire suspending the cleaning apparatus, the greater will be this difficulty.
If the prior art cleaning apparatus is used for a building in which windows are horizontally continuous, there arise a further problem that it is extremely difficult to clean corner portions of the building.
It is, therefore, an object of the invention to provide a horizontally moving automatic outer surface cleaning apparatus capable of realizing cleaning of a window glass effectively and smoothly even if windows are horizontally continuous ones.